#
# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Outer join via combine.

Phones(person: "Peter", phone: "4251112222");
Phones(person: "John", phone: "4251113333");
Emails(person: "John", email: "john@salem.org");
Emails(person: "James", email: "james@salem.org");

People(person:) distinct :- Phones(person:) | Emails(person:);

@OrderBy(PersonPhoneAndEmail, "person", "DESC");
PersonPhoneAndEmail(person:, phone:, email:) :-
  People(person:),
  phone == (combine AnyValue= p :- Phones(person:, phone: p)),
  email == (combine AnyValue= e :- Emails(person:, email: e));
